Processed cheese can be prepared by blending various cheeses and other dairy products with other components and processes. A finished processed cheese product can sometimes have different characteristics than found in a typical unprocessed cheese. Such characteristics can include differences in melt and fat separation over time, or at increased temperatures, as compared to unprocessed cheese. It is often desirable to adjust these characteristics of a resultant processed cheese to reflect product specifications and/or consumer expectations.
For example, “oiling-off” refers to separation of fat from a product (such as a cheese) in the form of a free oil. Oiling off can occur over time, or at increased product temperatures. In some instances oiling-off can be expected, such as cheeses exposed to high temperatures like those found in a pizza oven, which can be about 500 degrees F. (about 260 degrees C.). Oiling-off can also be associated with the overall stability of a cheese product over time.
Attempts are known in the art to control oiling-off, such as by an enzyme treatment. For example, U.S. Pub. 2008/0299252 to Fatum et al. describes improving fat stability in cheese by providing an enzyme treatment, such as a phospholipase C and/or D, to a “cheese milk”, to deplete phospholipids in the cheese milk.
Melt characteristics are also an important aspect of a cheese product. A “melt value” can be described in a number of ways, such as the ratio of an area of a melted cheese to the area of the un-melted cheese when subjected to certain standardized heating conditions (See generally, U.S. Pat. No. 4,885,183 to Strandholm, et al.). In Strandholm et al., the term “melt value” can be the ratio of the area of the melted cheese to the area of the unmelted cheese, using a piece of cheese of a predetermined sample size (for example, about 6.4 mm thick and 42 mm diameter), which is placed in a covered petri dish for 5 minutes in an oven at a temperature which is suitable for the type of cheese, i.e. usually a temperature of from 350 degrees F. (about 177 degrees C.) to 450 degrees F. (about 232 degrees C.). A melt value of 1.0 indicates no melt of the cheese section occurs, whereas a melt value of 2.0 indicates that a doubling of area occurs during the melt test. The same type of melt test can be carried out in a microwave oven using the same sample size cheese placed in a petri dish and typically heating for 30 seconds on maximum power in a 700 watt oven. (See generally, Strandholm, et al., col. 5, beginning line 6). Other methods can include measuring the diameter or radius of a melt area under controlled conditions and compared among samples (see below).
One way to control melt characteristics of a processed cheese can be through homogenization at various defined pressures during its production. It is known that increased homogenization pressure increases melt restriction. In other words, cheese products that are exposed to homogenization during production typically melt less in proportion to increasing homogenization pressures. Nevertheless, as homogenization pressure increases, there can also be decreases in the cheese product's stretchability and oiling-off, as well as increases in cheese whiteness. Lecithin has been used in some instances to improve meltability of recombined cream that is homogenized before making a cheese product. In this instance, some unknown level of a phospholipids coating (lecithin) is added to an anhydrous milk fat (AMF) of an already homogenized natural cheese milk. (See generally, The Role of Homogenization in the Manufacture of Halloumi and Mozzarella Cheese from Recombined Milk. J. of the Society of Dairy Tech., Vol. 43, No. 1, February 1990)
Other considerations in the development of homogenized and cooked cheese products and methods are a product's desired organoleptics, firmness and protein and fat microstructure. The processes described above show significant advances in the art, but further advances are possible and desired.